Telephone systems have become a central means for communicating with others on a real-time basis. However, for a variety of reasons, it is generally not possible or convenient for subscribers to answer every telephone call received. For example, with the high volume of junk calls (e.g., telemarketing, wrong numbers, and the like) many subscribers choose not to answer an incoming call. Subscribers may screen their calls using an answering machine that allows them to monitor the message as the caller records it. If the subscriber then recognizes the caller as someone he wants to speak to, he can override the answering machine and take the call. Answering machines have also been beneficial in those circumstances where the subscriber is not available to receive a call. In that case, the caller can still leave a message for the subscriber.
However, answering machines are vulnerable to malfunction due to loss of power, depleted recording media, and the like. Furthermore, if the subscriber's line is busy, the caller cannot get through to leave a message on an answering machine. To solve these problems, telecommunications service providers have developed network-based voice messaging systems (VMS). Such systems are generally maintained in controlled environments with adequate backup power supplies and redundant systems for high reliability. Furthermore, VMS systems may be configured to receive inbound calls when the subscriber's line is not available. Accordingly, conventional VMS systems have greatly improved the capabilities for subscribers to ensure callers can leave a message when the subscriber does not answer a call. A problem remains, however, for those subscribers who desire the capability to monitor messages as they are being recorded and the capability to intervene in the call to speak to the caller.
FIG. 1 shows how conventional voice messaging services operate. PSTN domain 100 includes telephony systems such as switches 102 and 104. Switch 102 serves the subscriber's telephone 106 and switch 104 serves voice messaging system (VMS) server 108. Switches 102 and 104, for example, may be the same switch or may be different switches as shown in FIG. 1. Switches 102 and 104 may be a circuit-switched service switching points (SSPs) such as the switches used in advanced intelligent networks (AIN) or may be a packet-switched network element. PSTN domain 100 also comprises PSTN 110 which may include for example, local exchange carriers, competitive local exchange carriers, long distance carriers, and the like. PSTN 110 may provide a network link between switches 102 and 104, as shown in FIG. 1.
When a caller, using, for example, telephone 116 calls the subscriber at telephone 106, the call will be processed by the subscriber's host switch 102 in the normal manner. If subscriber line 106a is busy or the call is not answered, the call is forwarded from switch 102 to VMS server 108 via PSTN 110 and switch 104. VMS server 108 may provide a message to the caller prompting him to record a message. VMS server 108 may also provide a variety of other options to the caller (e.g., message priority, replay recorded message, and the like).